Computer simulation of new schemes for generation of superintensive laser pulses

ABSTRACTA possibility for compression of self-modulated pulses with Joule energy and duration about 1 psec to durations lessthan 100 fsec is shown. Variation ofthe compression degree and of contrast of such pulses was studied in dependence on their shape, parameters of the medium, type of applied compressor, and limitations by competing nonlinear processes. The effect of supercompression of self-modulated and modulated pulses by means of a compressor of aspecial type was found. The possibility of SBS compression of laser pulses with super-high power was found.Keywords: pulse generation, CPA, phase modulation, supercompressionI. INTRODUCTIONAt present, application of the technique for chirped pulses amplification made possible to create compact solid-statelasers that give ultrashort laser pulses with superhigh intensity."4 The basic scheme of such lasers includes thefollowing stages: generation of short pulses with low energy; expansion and chirping; amplification up to considerable energy; and, finally, compression to durations comparable with initial one and reaching high powers.Initially, pulse expansion was performed in fiber light guides by means of nonlinear phase modulation.' Later, othermethods with application of diffractive gratings appeared. They permitted to advance to the domain of shorter pulses.At present, the shortest pulses (< 0.1 ps) were obtained by application of spectral broad-band crystals, such as TiA12O3or LiSAF, and the pulses with the highest energies (duration I ps) -byapplication of Nd glasses. The authors of Ref.20 proposed additional compression of picosecond pulses of considerable energy by means of nonlinear phase